Redding Competition Micrometer Seater Die with part prefix # 55XXX or the in case of 9x19 55172. These dies have no crimp function at all.
Other Redding seater dies do have a crimp function except for "Pro Series Dies" i which have a part prefix # of 89XXX for the set which is
dies that radiused for use in a progressive press. You get sizer/decapper, seater only die, and a crimp die.
Redding Pro Series Competition sets are similar with part prefix # of 58XXX, but they come with a Competition Seater die instead.
The new premium sets with part prefix # 66XX are regular dies so to speak
They come with a regular sizer/decapper, a premium expander die, and a seater with a Micrometer Seater Plug meant for seating and crimp die